This invention relates to continuous curb laying machines and methods therefor, more particularly, to such machines and methods wherein pieces of expansion joint material may be inserted at intervals into the cast green concrete curb without stopping the apparatus, and it is an object of the invention to provide improved apparatus and methods of this nature.
Continuous curb laying machines are known to the art. Concrete curbing is poured or cast, in a relatively stiff consistency so that it will retain its shape without significantly slumping after the slip form has passed over it. Typically, in the past, expansion joints have been formed in ribbons, or lines, of poured, or cast concrete curbing by hand operations. That is to say, after the concrete curbing has been poured, a workman with a trowel, or similar tool forms a slot in the concrete and inserts a piece of expansion joint material which is essentially a relatively stiff felt board. After the joint material has been inserted, the workman backfills the space on each side thereof with concrete from the original slot formation or from a supply that he may have at hand. In any event, the concrete on each side of the joint material must be smoothed and curved to fit the outline of the curbing in order for the job to appear finished and to have been correctly made. Not only in this process relatively tedious and expensive, but is it time consuming and it requires careful work.
It is also known to the prior art to have a machine for inserting an expansion joint into a road surface that has been cast, or poured, from concrete or the like. Because of the relatively wide expanse of road surfaces, machines for inserting expansion joint material or pieces have been of equal length, and thus, the apparatus for insertion of the joint material has been bulky and complicated. Schemes for supporting the expansion joint material during the insertion process have been complicated and have not lent themselves to utilization in curb forming apparatus because the curbing, ordinarily, has a shape different from straight or flat.
Certain expansion joint inserting machinery is known to the art. Reference may be made to U.S. Pat. Nos. 2,014,894 Heltzel, 3,200,482 Brown, 3,246,390 Brown, 3,335,647 Thorp, Jr., 3,473,450 Koch. In each of these patents road surfaces are poured first and a second machine is utilized to insert the expansion joint. In each case a slot or channel is first formed or the concrete previously treated at the place of insertion. Clearly these solutions are cumbersome and relatively inefficient when compared to the applicant's continuous apparatus and method.